Research will be focused on efforts to obtain preimplantation development of rabbits embryos in vitro. Preimplantation development and subsequent embryo transfer will be related to conditions prior to in vitro fertilization (IVF), embryo culture conditions and the nutritional status of the embryo. Oocytes will be recovered from hormonally treated New Zealand White (or Dutch Belted) does. The conditions to which unfertilized oocytes are exposed will be carefully controlled to determine the effects on IVF and embryo development. Oocytes will be inseminated with in vivo or in vitro capacitated spermatozoa under conditions known to support in vitro fertilization. The resulting zygotes will be cultured initially under conditions reported to support early development in the rabbit and/or other mammalian species. Their subsequent development after embryo transfer (ET) and/or ability to reach the blastocyst stage will be used as indices of nutritional health, as will free amino acid content, protein content, and amino acid transport rates. Key components and/or conditions will be varied to identify those which support and ensure viable development. Furthermore, the use of micromanipulation of gametes for IVF will be explored along with the subsequent effect of such manipulations on embryo development and viability. Data anticipated from these efforts should prove useful in extending and improving present methodologies of IVF, embryo culture and embryo transfer in cattle and other large domestic species. Such information may also help improve the success rate of clinical IVF in human patients.